Method for producing dials

ABSTRACT

A METHOD FOR PRODUCING DIALS HAVING HOUR SYMBOLS COATED WITH A METAL OTHER THAN THE METAL COATING THE DIAL GROUND OR PLATE, WHEREIN MASKS ARE FORMED ON MASTER DIALS AND APPLIED TO DIALS TO BE PRODUCED WHEREAFTER SAID METAL IS VAPOUR DEPOSITED ON SAID HOUR SYMBOLS.

July 18, 1972 w. BLscH METHOD FOR PRODUCING DIALS Filed Feb. 6, 1970 Viv nted States Patent @Hice ,n 3,677,793 Patented July 18, 1972 9 Int. Cl. B44d 3/30; B32b 31/00 U.S. Cl. 117-38 0 Claims ABSTRACT 0F THE DISCLOSURE A method for producing dials having hour symbols coated with a metal other than the metal coating the dial ground or plate, wherein masks are formed on master dials and applied to dials to be produced whereafter said metal is vapour deposited on said hour symbols;

This invention relates to a method for producing dials of which the ground or plate and hour symbols are made in one piece of plastic material.

Dials of this type are known of which the ground or plate and thehour symbols are metallized. Usually the ground or plate is coated with silver while the hour symbols are coated with gold or chrome. Since the problem of providing a sufficiently accurate and reliable mask and of an economic production of such a mask could not be solved in a satisfactory manner up to now, the plate was usually coated with silver and afterwards the hour symbols were produced with a gold coating by means of a transfer printing process or a gold-coloured aluminium foil was applied to the hour symbols by means of a thermopress.

However, with these methods it is impossible to obtain sharp and brilliant hour symbols of plastic material. Either method resulted in surfaces having a cheap and unesthetical appearance. At least applying of a foil as mentioned above is more expensive than metallisation of the hour symbols with the use of masks.

A prior method operating with masks of insulating matterial for electrolytically metallizing the hour signs is practically inoperable, because it is impossible to clearly control the metal deposit at the upper surface only or also at the side surfaces. Further it appears impossible to provide masks so tightly covering the dial ground or plate and the hour symbols that no electrolyte may leak down to the dial ground or plate. However, any leakage would result in objectionable local metalization of the ground.

This invention aims in providing an economic method for producing dials of plastic material having high-quality brilliant hour symbols. This method is broadly characterized in that the side carrying the hour symbols of at least one master dial is completely covered with a masking material, whereafter this masking material is separated from the master dial and is removed within reach of the hour symbols until apertures of a shape corresponding to the 'shape of the hour symbols are formed, whereafter the so produced mask is repeatedly applied to the side carrying the hour symbols of dials with the walls dening said apertures closely mating the hour symbols of such dials, a coating being vapour-deposited onto the unmasked por'- tions of the hour symbols of each dial while a mask is applied thereto. This allows moulding of the dials by injection or stamping of plastic material in their final form with facets, whereafter the whole front side of the dial may be metallized in a `rst colour, for instance with silver, whereafter the mask may be applied and according to the form of the mask the uncovered portion of the hour symbols, namely either the faceted upper surface thereof only or the whole hour symbols may be metallized in another colour, for instance with gold or chrome. In this way the total manufacturing costs may substantially be reduced. Preferably thev masks are electrolytically deposited on the master dials. The master dials may be taken from a standard manufacturing series of dials so that the masks for thisA series'are fully adapted in shape to the dials of his series.

This invention will now be described in detail with reference to the accompanying drawing illustrating an example and two modifications of the method.

FIGS. 1`to 5 illustrate steps of the manufacturing example, 'A

FIG. 6 illustrates a first modification and FIG. 7 a second modification.

FIG. 1 shows a' dial of the series to be manufactured in sections. The ground or plate 1 of the dial is injectionmoulded or stamped of plastic material in one piece with the hour symbols 2 which may be faceted at their upper surface in any desired manner. The dial ground has an annular protecting rim 3 with upwardly extending orienting pins 4 and 5. As shown in FIG. 1 these orienting pins may be of different diameter. Alternatively more than two orienting pins may be provided in predetermined geometric disposition. As an example, three pins may be disposed in the corners of an irregular triangle. The dial of plastic material shown in FIG. 1 is now metalized by vapour deposit at its upper side provided with the hour symbols, Whereafter a copper layer of about l mm. thickness is electrolytically deposited. In this Way the stage -shown in FIG. 2 with a copper layer 6 is obtained. The

higher portions of this layer on the orienting pins 4 and 5 and on the hour symbols 2 are now faced off until the plastic material of pins 4 and 5 are of the hour dials respectively just appears below the copper layer. This stage is illustrated in FIG. 3 wherein the worked copper layer is still assembled with the master dial. The master dial is now solved in a suitable solvent for plastic material so that the copper mask 6 shown in FIG. 4 remains. Any suitable plastic material may be used Afor the dial and any solvent well known in the art for this plastic material may be used for :solving the dial. It has apertures 2', 4 and 5 of which the shape exactly corresponds to the shape of the hour symbols Z, and pins 4 and 5 respectively. This mask is now slightly etched in a chemical etching agent in order to remove f'oo to yoo of a millimeter, whereby apertures 2', 4 and 5 are slightly widened. Now, a vapour deposit of 2 to 3p. of gold or nickel is applied to each mask produced as described above, according to the lat-ter use of the masks, that is, according to the metal to be applied to dials masked by such masks.

The so prepared masks may be applied easily and with very small clearance to injection-moulded or stamped plastic dials as shown in FIG. 5, the form of such dials corresponding exactly to the form of the dial shown in FIG. 1. When applying the mask onto a dial, the orienting pins 4 and 5 of the dial first enter into the orienting apertures 4 and-5 of the mask whereby the mask is precisely oriented in a predetermined position above the dial. Only now the hour symbols 2 of the dial may enter into the corresponding apertures 2 of the mask, and since such apertures are preciselyoriented the hour symbols cannot be damaged. When the mask is applied, a metal coating, for instance of nickel, chrome or gold is vapour-deposited on the unmaskedupper surface of the hour symbols. The other portions of the dial surface previously coated with another metal, for instance silver, are completely protected by the mask. In this way, a two-colour dial is obtained having for instance a silver ground and hour symbols coated with gold, nickel or chrome.

The same mask may be used several times. Assuming that about 0.1; of metal is vapour-deposited on each dial, the mask may be used about times until a layer of about IAO() mm. additionally deposited Yon the mask begins'to hinder applyingof themask onto dials. However, this additional metal deposit` may be removed from the mask in a suitable etching bath. If the mask serves for vapour depositing gold it is initially coated with nickel or is'made electrolytically from nickel. In this case the gold coating applied to the mask during vapour-coating of dials may electrolytically be removed in concentrated sulphuric acid wherein the nickel surface of the mask is not attackedrlf the mask is used for vapour-depositing chrome or nickel onto the dials, the mask is initially provided with a gold coating. If nickel kor chromeis vapour-deposited on the hour symbols of masked dials the layer of any one of these metals deposited on vthe mask may periodically be removed in a suitable etching bath, for instance in nitric acid or hydrochloric acid, wherein the gold-coated surface of the mask is not attacked.

The mask illustrated in FIG. 4 has apertures 2 of a -depth practically equal to the height of the. hour symbols 2 ofthe dial so that the side surfaces of the hour symbols are masked and the vapour-deposit of metal is only applied to the top surface of the hour symbols. However, in many cases,-it isv desired to metalize the Whole hour symbols in another colour than the dial ground. In this case the mask is faced off to a very small thickness within reach of the hour symbols as shown in FIG. 6, in which case the side surfaces of the hour symbols are also metallized. This mask may have a thickness in the order of 5A00 to 1/10 of a millimeter. In order to obtain a mask of suicient rigidity it may galvanically be produced in a soft nickel bath and stifening ribs may be soldered to it.

On the other hand the depth of apertures 2 of the mask may substantially exceed the height of the hour symbols 2 of the dial to be produced, as shown in FIG. 7. In this way an even higher masking effect is obtained for the side surfaces of the hour symbols for preventing any trace of metalization of such surfaces. FIG. 7 also illustrates that the mask metal above the orienting pins 4 and 5 must not necessarily be removed so that dry holes are obtained instead of apertures 4 and 5. Of course other apertures of the mask corresponding to parts or symbols of the dial, such as calendar windows, trademark signs and the like may be provided.

Instead of circular, complete masks, semi-circular or annular masks may be used so that in addition to the hour symbols the dial ground is metalized on one half of the dial or in the center thereof respectively in the same colour as the hour symbols. In this way various elects may be produced.

As shown in FIGS. 1 and 5, the master dial has somewhat lower hour symbols than the dial to be produced. However, exactly the original dial illustrated in FIG. 5 may be used for deposition of the mask thereon whereby only the higher portions of the original metal deposit must be turned olf to the desired level in order to obtain the desired depth of the apertures 2 of the mask.

While it has been assumed in the foregoing that the mask is produced by electrolytic deposit on a dial of plastic material, a mask of plastic material might also be formed on a suitable master dial.

What I claim is:

.1. A method for producing dials of which the plate and hour symbols are made in one piece of plastic mas,677v,793 d hterial, wherein the side carrying the hour symbols of at least one master dial is completely covered with a masking material, whereafter the master dial is removed from said masking material and said masking material is worked off within reach of the hour symbols until apertures of a shape corresponding to the shape of the hour symbols are formed, whereafter the so produced mask is repeatedly applied to the side carrying the hour symbols of dials with the walls defining said apertures closely mating the hour symbols of such dials, a metal coating being vapourdeposited onto the unmasked portions of the hour symbols of each dial while a mask is applied thereto.

2. A method according to claim 1, wherein said masking material is applied to master dials taken from a standard manufacturing series of dials.

3. A method according to claim 1, wherein said master dials are covered with a masking metal from which said masks are produced by removing metal within reach of the hour symbols.

4. A method according to claim 3, wherein said masking metal is removed within reach of the hour symbols while the masking metal is still on said master dial, whereafter the master dial is solved.

5. A method according to claim 1, wherein said dials and master dials are produced with a rim portion surrounding said plate, whereby this rim portion is provided with orienting pins, said masking material being also applied to said rim portion and orienting pins respectively for producing orienting holes herein where said orienting pins engage the masking material.

6. A method according to claim 3, wherein said masks are slightly etched prior to applying themonto dials, in order to slightly Iwiden their apertures.

7. A method according to claim 1, wherein masks are produced and used having apertures of a depth exceeding the height of the hour symbols of the dials to be produced.

8. A method according to claim 1, wherein metal coatings are vapour-deposited on said hour symbols, the metal coating thereby deposited on said mask being periodically removed.

9. A method according to claim 8, wherein gold is vapour-deposited and masks of nickel or coated with nickel are used, the gold coating on such masks being periodically removed electrolytically in concentrated sulphuric acid.

10. A method according to claim 8, wherein chrome or nickel is vapour-deposited and a mask coated with gold is used, the chrome or nickel coating on the masks being periodically etched away in hydrochoric acid.

References Cited UNITED STATES PATENTS 3,354,544 10/1967 Jones et al 117-38 3,302,612 2/ 1967 Stutzrnan 117-38 2,689,805 9/1954 Croze et al. 117-38 3,531,311 9/1970 Prior ll7-8.5

ALFRED L. LEAVITT, Primary Examiner M. F. ESPOSITO, Assistant Examiner U.S. Cl. X.R. 

